I was legitimately looking to have major renovation done on my condo (triple glazed windows, sound insulation added elsewhere, etc) before I got a white noise machine. Before, I'd be woken up at 730am (following a 2am prod deployment) by some jackass cranking a leaf blower the very second the noise ordinance allowed. Now I usually sleep peacefully to my alarm. I don't really care whether there's scientific evidence of it working, it's saved my sanity.

Two things to look out for: 1. Make sure it's a non-looping white noise machine. The looping ones drive me crazy 2. Mine can play lower frequencies which really help block out external noise.